CO2 enrichment in vitro. Effect on autotrophic and heterotrophic cultures of Nicotiana tabacum (var. Samsun).

Plantlets of Nicotiana tabacum (var. Samsun) were grown under CO2 enriched air supplied by a Warburg buffer. Growth of all plant parts was enhanced. The maximum growth increase was found for roots (120%).Addition of 30 g.l(-1) sucrose in the medium resulted in a three time faster growth. However, the effect of CO2 enrichment was still positive in these conditions, although less pronounced than in autotrophic cultures.